In a large saucepan, combine the sugar, honey, and 2 cups water and place over medium-high heat. Cut the vanilla bean in 1/2 lengthwise, then, using the back of the knife, scrape the vanilla seeds from the pod and add to the saucepan, along with the pod. Bring the mixture to a boil and cook for 4 or 5 minutes, until the sugar is dissolved and the mixture thickens. Remove from the heat and allow to cool.
Put the lemon juice into a gallon jug or pitcher. Pour the sugar syrup through a strainer into the pitcher and discard the pod. Add water to equal 1 gallon and stir well.